要在因特网上发电子邮件,首先必须知道收件人的用户名和他所在的主机名。然而,与UUCP网络不同的是,在因特网上发邮件不必知道在你和收件人之间连接的所有主机名。邮件地址是这样构建的,首先输入收件人用户名,紧跟一个“at”符号(@),然后是收件人的主机名和所在机构的域名,该域 To email on the Internet, you must first know the recipient’s user name and his hostname. However, unlike UUCP networks, sending mail over the Internet does not have to know all the host names that connect you to the recipient. The email address is constructed by first entering the recipient user name, followed by an “at” sign (@), then the recipient’s host name and the institution’s domain name, which